The PMT gene family: protein O-glycosylation in Saccharomyces cerevisiae is vital

EMBO J. 1996 Nov 1;15(21):5752-9.


The transfer of mannose to seryl and threonyl residues of secretory proteins is catalyzed by a family of protein mannosyltransferases coded for by seven genes (PMT1-7). Mannose dolichylphosphate is the sugar donor of the reaction, which is localized at the endoplasmic reticulum. By gene disruption and crosses all single, double and triple mutants of genes PMT1-4 were constructed. Two of the double and three of the triple mutants were not able to grow under normal conditions; three of these mutants could grow, however, when osmotically stabilized. The various mutants were extensively characterized concerning growth, morphology and their sensitivity to killer toxin K1, caffeine and calcofluor white. O-Mannosylation of gp115/Gas1p was affected only in pmt4 mutants, whereas glycosylation of chitinase was mainly affected in pmt1 and pmt2 mutants. The results show that protein O-glycosylation is essential for cell wall rigidity and cell integrity and that this protein modification, therefore, is vital for Saccharomyces cerevisiae.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism
  • Genes, Fungal*
  • Glycosylation
  • Mannosyltransferases / genetics*
  • Mannosyltransferases / metabolism*
  • Molecular Sequence Data
  • Multigene Family*
  • Mutation
  • Phenotype
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae / metabolism*


  • Fungal Proteins
  • Mannosyltransferases
  • protein O-mannosyltransferase

Associated data

  • GENBANK/L05146
  • GENBANK/L19169
  • GENBANK/U28374
  • GENBANK/X83797
  • GENBANK/X83798
  • GENBANK/X92759
  • GENBANK/Z49133